In this Monday, Aug. 12, 2019, photo, plumes of smoke rise after an explosion at a military base southwest of Baghdad, Iraq. (Loay Hameed/AP)

Iraq on Thursday banned unauthorized flights and ordered all military camps and munitions warehouses to be moved outside Iraqi cities following a massive explosion at a munitions depot southwest of Baghdad that killed one civilian and wounded 13 earlier this week.​The exact cause of Monday night's explosion at the al-Saqr military base is still unknown. The blast shook the Iraqi capital and sent explosives and mortar shells shooting into the sky, damaging nearby homes and terrifying residents who ran into the streets with their cellphones. Black smoke billowed over the city for hours afterward.

The federal police base houses a weapons depot belonging to a militia group under the umbrella of the mainly Iran-backed militias known as the Popular Mobilization Forces. The state-sanctioned PMF militias have fought alongside Iraq’s regular armed forces against the Islamic State group.

​Some officials blamed the explosion at the base, also known as Falcon Camp, on faulty storage that caused overheating amid typically high temperatures in Baghdad. But the blast has also given rise to a host of theories, including that Israel may have conducted an airstrike.

Israel has struck Iranian bases in neighboring Syria on numerous occasions, and there has been speculation that it might be expanding its campaign to target Iranian bases to Iraq. However, neither the Iraqi government nor Israel have addressed the reports.

Iraqi Prime Minister Adel Abdul-Mahdi ordered a "thorough investigation" into the incident, ordering the investigation be concluded within a week.

In a statement issued Thursday following a national security meeting, Abdul-Mahdi ordered the cancellation of all aviation approvals for flights throughout the country, unless authorized by the commander of the armed forces. The statement did not specify military or civilian flights but specifically cited reconnaissance, fighter jets and helicopters and drones of all kinds.

​It said the directives applied to "Iraqi and non-Iraqi parties." Iraq hosts American troops and forces belonging to the coalition fighting the Islamic State group, which sometimes conduct operations and airstrikes in the country.

The statement urged all parties to abide by the directives, stating that any other flight activity "will be considered (an) enemy flight and dealt with from our air defenses immediately."

The statement called for the transfer of warehouses and camps belonging to the defense and interior ministries and the PMF and other factions that participated in fighting IS to be moved outside the cities. It said violators will be "considered an irregular presence and dealt with in accordance with the law and order."

Abdul-Mahdi also ordered that citizens who suffered human and material damage from the explosion be compensated.

A PMF official said their initial investigation showed a drone strike was responsible for Monday's blast, adding that blaming it on faulty storage was a way to avoid embarrassing the government. He estimated the losses to be in the millions and spoke on condition of anonymity because of the sensitivity of the information.

Abu Alaa al-Walae, a PMF commander, described in a tweet Abdul-Mahdi's "decision to ban American drones in Iraqi airspace" as brave.

Monday's blast is the latest of several mysterious explosions that have taken place recently at PMF bases in Iraq. Last month, an explosion took place at a base in Amirli, in Iraq's northern Salaheddin province, killing two Iranians and causing a huge fire.

That attack was blamed on an unmanned drone that dropped explosives, with some Shiite militias blaming it on the Islamic State group.